Question

A convex mirror with a focal length 20 cm creates a virtual image 10cm away from the mirror. What is the position of the object?

Answer 1

Answer:

$20$ cm

Explanation:

$d_{o}$ = distance of the object = ?

$f$ = focal length of the convex mirror = - 20 cm

$d_{i}$ = distance of the image = - 10 cm

Using the lens equation

$\frac{1}{d_{o}} + \frac{1}{d_{i}} = \frac{1}{f}$

$\frac{1}{d_{o}} + \frac{- 1}{10} = \frac{- 1}{20}$

$d_{o} = 20$ cm